There are many k-pop idols who write their own songs and make big hits with them, while most of their fans might think, "Oh, my oppa is so good at composing songs." By the way, there is a secret about k-pop idols' own songs.
When an idol says "I wrote my own song," you might think he took charge of making the whole thing. Well, but it's not true. Music composition is a complicated work. If you want to compose a song, you need to study harmony and counterpoint first, while you should learn how to play musical instruments and use computer programs too.
However, as a matter of fact, most of k-pop idols, who say they write their own songs have no knowledge of harmony and counterpoint, and they don't know how to play musical instruments either. During composing their own songs, all they do is just take part in coming up with some melodies. That's why they can't write songs alone and professional composers always take part in making the idols' own songs as arrangers. Actually, with a shame some of idols do little to make their own songs.
Oh, don't get me wrong. I'm not saying all the kepop idols are terrible composers and their own songs are fakes. First, not all the k-pop idols are ignorant about music theory. Some of idol composers have wide knowledge about music and they do play a leading role in making their own songs. Second, there are some idols who show an exceptional ability in coming up with good melodies even though they don't have an exclusive knowledge of music. Even professional composers praise them, saying, "The young and fresh idols always come up with a brilliant idea.“